Synchronous bilateral inverted papilloma of the temporal bone: Case report and review of the literature.

BACKGROUND Temporal bone inverted papilloma (IP) is an extremely rare tumor. Its etiology is unknown and represents a source of debate. Only 2 previous cases of bilateral temporal bone IP have been reported. A case report and review of the literature via PubMed database search are presented. MATHODS AND RESULTS A 52-year-old African-American man who initially underwent medial maxillectomy for right-sided nasal IP returned with bilateral temporal bone IP 7 months later without evidence of extension through the Eustachian tubes. Despite multiple resections and adjuvant radiation, the tumor transformed into squamous cell carcinoma and progressed to involve the intracranial dura, temporal lobe, and cervical dura. CONCLUSIONS Multiple origins may exist for temporal IP: direct extension, iatrogenic seeding, or development from ectopic Schneiderian epithelium. Temporal bone IP appears to represent a much more aggressive tumor than its nasal counterpart, necessitating aggressive early surgical intervention to decrease recurrence and transformation risk.